14 Grizzly 450 will only run under full throttle.

[Cobra_kai83]

The gas in the tank was bad so I drained it and put new fuel in. It still wouldn't run so I took the carb out and cleaned it. Re-installed the carb and now it will only start and run under full throttle. It also runs rough like this. The engine stops running once I back out to 1/4 throttle. What the heck is going on?

[Mech]

Well under those circumstances, and with those symptoms, it's most likely that you have introduced an air leak into the inlet manifold, or the carb might need redoing.

If the carb is a diaphragm type you might take the top off in place first, then if you find nothing there, like a loose needle or with any spacers wrong, take the carb off and check the inlet connection, then strip the carb and recheck your work.

[Gwbarm]

I would also check to make sure you are getting consistant firing at the plug, and also check the compression.

[Mech]

Yeah good point Gw. The bad fuel could have fouled the plug..